Backport PR matplotlib#32058: MNT: Fix handling of ints in hsv_to_rgb()

Author: QuLogic

lib/matplotlib/colors.py

@@ -3729,11 +3729,10 @@ def hsv_to_rgb(hsv):
                          f"shape {hsv.shape} was found.")
 
     in_shape = hsv.shape
-    hsv = np.array(
-        hsv, copy=False,
-        dtype=np.promote_types(hsv.dtype, np.float32),  # Don't work on ints.
-        ndmin=2,  # In case input was 1D.
-    )
+    # ensure numerics are done at least on float32; ints are cast as well
+    hsv = np.asarray(hsv, dtype=np.promote_types(hsv.dtype, np.float32))
+    if hsv.ndim == 1:
+        hsv = np.expand_dims(hsv, axis=0)  # ensure hsv is 2D
 
     h = hsv[..., 0]
     s = hsv[..., 1]

lib/matplotlib/tests/test_colors.py

@@ -946,6 +946,11 @@ def test_rgb_to_hsv_int():
     assert_array_equal(mcolors.rgb_to_hsv((0, 1, 0)), (1/3, 1, 1))  # green
 
 
+def test_hsv_to_rgb_int():
+    # Test that int hsv values (still range 0-1) are processed correctly.
+    assert_array_equal(mcolors.hsv_to_rgb((0, 1, 1)), (1, 0, 0))  # red
+
+
 def test_autoscale_masked():
     # Test for #2336. Previously fully masked data would trigger a ValueError.
     data = np.ma.masked_all((12, 20))